Bulletin d’avalanche

Cariboos

Mar 5 – 6, 2023Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Tue
Wed
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré

Points saillants

Avoid wind loaded features on all aspects, winds are expected to vary. Steer clear of sun affected slopes if skies clear, even short bursts of sunshine may increase reactivity.

Deep persistent weak layers continue to be a concern in this region. Read about managing this problem in our latest Forecasters' Blog.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2

    Recent storm snow has been affected by variable winds. Expect deeper wind affected deposits on many slopes. Sheltered terrain produce loose dry avalanches - be prepared to manage your sluff.

    Additionally areas that see clear skies and strong sun should avoid sun affected slopes. Surface snow may rapidly lose cohesion.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–4

    A weak layer of facets exists near the base of the snowpack. The likelihood of human triggering is low given the layer's depth, but smaller avalanches in motion have the potential to step down creating very large avalanches. Suspect terrain for human triggering includes steep, shallow and rocky terrain.

Confidence

Moderate

Avalanche Summary

On Thursday and Friday, storm and wind slabs were reported to size 2.5 from natural and human triggers. Operators reported rapid loading due to winds at higher elevations but observations have been limited due to visibility and weather. We expect a natural cycle to have occurred primarily in wind loaded features.

Deep persistent slab avalanches were observed over a week ago, occurring during the very windy arctic outflow event.

Snowpack Summary

Variable winds have redistributed recent storm snow into deeper deposits on many aspects. This storm snow sits over wind effected surfaces and a thin sun crust on steep south facing slopes.

Around 40-90 cm deep a layer of small surface hoar exists in lower elevation sheltered areas. Elsewhere heavily wind effected surfaces exist, with faceted (sugary) snow from the late February Arctic blast. Reports suggest this interface has not yet been reactive.

The remainder of the mid-snowpack is considered generally strong with a small surface hoar layer from mid February that appears to be spotty and is not producing avalanche activity.

A layer of large and weak facets that formed in November sits near the base of the snowpack. Although the likelihood of triggering this layer is low at this time, the consequence of doing so remains very high. This layer is most likely to be human-triggered in thin, rocky slopes at alpine and upper treeline elevations.

Weather Summary

Saturday Night

Light easterly winds, gusting moderate. Freezing levels below valley bottom.

Sunday

A mix of sun and cloud. Light easterly winds. Freezing levels below valley bottom, alpine high of -8 °C.

Monday

A mix of sun and cloud. Light to moderate southerly winds. Freezing levels below valley bottom, alpine high of -6 °C. Possible flurries.

Tuesday

Mostly cloudy with moderate southwest winds. Freezing levels below valley bottom, alpine high of -4 °C. Flurries.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.

Régions couvertes